Field of Art
The present disclosure relates to an ocular characteristics measuring apparatus for measuring ocular characteristics of an eye to be examined.
Description of the Related Art
Recently, an increasing number of eyes to be examined have intraocular lenses inserted therein as intraocular lenses (IOL) for cataract operation have become widely used. Hereafter, an intraocular lens is referred to as an “IOL” and the eye to be examined in which an intraocular lens is inserted is referred to as an “IOL eye.” The IOL differs from the crystalline lenses in characteristics, such as shape, material and existence of refractive power adjustability. Therefore, in order to measure the IOL eye with high precision, it is necessary to use a measuring method in consideration of characteristics of the IOL eye.
Japanese Patent No. 3244873 proposes a technique about an eye refractivity measuring apparatus in which an examiner inputs, into the apparatus, whether an eye to be examined is an IOL eye, and the device switches functions of a jog dial in accordance with the input. Therefore, the examiner may adjust light intensity of a fixation target using the jog dial with respect to the IOL eye which is typically subject to contraction.
Techniques to avoid contraction of the pupil have been proposed to prevent making measurement of ocular refractivity difficult.